You would probably have a hard time finding something so specific for sale. The software involved is not that complex. If you know a little HTML, CSS, and JavaScript you could probably find an example of the code required by searching on "JavaScript div show hide tutorial". If you don't do your own coding, you could probably hire it done for a reasonable fee on one of the freelance sites or the Commercial Exchange [webmasterworld.com] forum here on Webmaster World.